This invention relates to liquid dispensers and in particular to devices for dispensing quantities of liquids, such as cleaning and/or freshening liquids, from under the rim of a toilet bowl.
Toilet bowls require care to prevent the buildup of unsightly deposits, to reduce odors and to prevent bacteria growth. Traditionally, toilet bowls have been cleaned, deodorized and disinfected by manual scrubbing with a liquid or powdered cleaning and sanitizing agent. This task has required manual labor to keep the toilet bowl clean.
In order to eliminate the manual scrubbing, various automatic continuous cleaning toilet bowl cleaning products have been proposed. One type of product comprises a solid block or solid particles of a cleansing and freshening substance that is suspended from the rim of a toilet bowl in a container that is placed in the path of the flushing water. U.S. Pat. No. 3,529,309 shows an example of this type of toilet bowl cleaning system. The solid cleaning blocks have a short lifetime and the release of cleaning and deodorizing agents drops off as the solid block deteriorates.
Toilet cleaning systems that use a liquid cleaning agent have also been developed. For example, European Patent Application EP-0538957 discloses a cleansing and/or freshening unit capable of being suspended from the rim of a toilet bowl for the purpose of introducing liquid active substances from a bottle into the flushing water with each flush. Another similar liquid dispensing toilet bowl cleaning system is described in European Patent Application EP-0785315. This application acknowledges that one problem with the device disclosed in EP-0538957 is that as the liquid level in the dispensing bottle falls, the rate at which liquid is dispensed falls with time.
The dispensing device described in EP-0785315 was developed as a proposed solution to this problem, and includes a dispensing bottle with a structure that permits both the flow of liquid from the bottle and a return flow of air from outside the bottle to inside the bottle.
While the dispensing device disclosed in EP-0785315 provides an alternative to the solid block toilet cleaning systems described above and to the liquid dispensing device disclosed in EP-0538957, it also has disadvantages. For instance, the device described in EP-0785315 requires the use of a porous, liquid-absorbing mass (i.e., a sponge) which always communicates with the cleaning liquid contained in the dispensing bottle and is located in the path of the flushing water of the toilet. This system is unduly expensive to manufacture and cannot provide precise control over the volume of liquids dispensed in the flushing water.
Therefore, there is a need for an improved device that can dispense a liquid cleaning, disinfecting and deodorizing substance into a toilet.